Programmable weft insertion brake for looms

ABSTRACT

A jet loom with a weft yarn insertion brake contains a braking element that is movable from a position of rest, on one side of the weft yarn, across the path of the weft yarn to a braking position. An electric motor, which drives the braking element, can be actuated during each insertion process of the loom. The electric motor preferably constitutes a fast response step or d.c. motor, whose direction of displacement can be switched and whose stroke can be individually adjusted for each set position of the braking element during the insertion process. Operation of the electric motor is controlled by an electronic control device. Programming within the control device can be modified between varying insertion processes so as to adapt the timing, stroke and driving direction of the electric motor. The driving force of the electric motor is transferred to the braking element by a constrained, inelastic link connecting the two. The electric motor is controlled so that the driving force exerted on the braking element is always greater in magnitude than the greatest possible reaction force of the deflected weft yarn.

FIELD OF THE INVENTION

The present invention refers to a loom with a programmable insertionbrake.

DESCRIPTION OF THE PRIOR ART

An air-jet loom according to EP-A1-03 56 380 includes a driving motor ofthe controlled insertion brake (e.g. a solenoid plunger for displacing abraking element) which, in its braking position, deflects the weft yarnand reroutes it at two stationary rerouting elements. For dampingtension peaks in the weft yarn, the deflection is at least partiallyeliminated, with the amount of elimination of the deflection beingadjusted or controlled. For adjusting and controlling the elimination ofthe yarn deflection in the insertion brake, which is controlled suchthat it occupies the braking position until the insertion process hasbeen finished, an elastically yielding energy accumulator is utilized.The energy accumulator is constructed such that it yields with a certaindelay to the force exerted due to the rerouting of the weft yarn. Thesaid energy accumulator may be a magnet or a spring whose excitation iscontrolled so that it will be stronger for initial braking and weakerfor the subsequent damping when the deflection is being eliminated. Fordamping the tension peaks, the force in the deflected weft yarn, whichincreases when the tension increases, is used for deforming the energyaccumulator, which dissipates energy and reduces tension peaks in areciprocal action. Even if the insertion brake acts on the weft yarnonly for the period of time actually required for braking and damping,the elastic energy accumulator will, after the reduction of a tensionpeak, generate a countermovement with a new tension peak in the weftyarn and with a retraction movement of the weft yarn into the shed. Itfollows that, in the case of this elastic damping, an additionalinterference is induced at the end of the insertion process because ofthe active participation of the weft yarn. Moreover, a jolt perceptiblein the weft yarn as well as noticeable mechanical wear in the insertionbrake are caused due to the fact that the insertion brake is moved sothat it strikes a stop means.

In an air-jet loom according to EP-A1-01 55 431, a cam-controlledinsertion brake is provided. A deflection lever of the insertion brakeis pivoted relative to stationary rerouting elements by a cam drive inaccordance with a program which is identical for all insertion processesand which has to be carried out completely during each insertionprocess. The insertion brake occupies a braking position at thebeginning of the insertion process and is gradually moved to itsposition of rest when the weft yarn is starts to move for the purpose ofinsertion. Towards the end of the insertion process, the insertion brakeis readjusted to a braking position where it will remain with increasingdeflection of the weft yarn until the next insertion process takesplace. However, a mechanically controlled insertion brake is not preciseenough for being used with modern jet looms having high insertion speedsand a high insertion frequency.

EP-A1-01 55 431, which has a prior time rank, discloses the measures ofpressing a brake pap, which is arranged on a bent lever and which iscontrolled via a lever mechanism, onto a countersurface and ofdecelerating by means of clamping the yarn passing through. The levermechanism is driven via a stepper motor with a resolver, in accordancewith the gripper movement, thus generating a specific braking forcecurve for the yarn. The stepper motor is controlled by programmedinstructions outputted by a logic circuit.

EP-A1-04 67 059, which has a prior time rank, discloses a yarn tensionregulating device also adapted for use with jet looms. It is providedwith a two-armed oscillating lever whose one end deflects the yarnguided across two stationary abutments, whereas the other end thereofcarries a magnet coil which is in alignment with two spaced permanentmagnets of a linear electric motor. In a normal position of the lever,in which the yarn is deflected, the two permanent magnets produce aneffect like a spring. When the yarn tension changes, the changingdeflection of the lever is compensated for by the current supplied tothe linear electric motor in such a way that the force exerted by thelever onto the yarn is brought into equilibrium with the force caused bythe yarn tension. The instantaneous yarn tension is calculated on thebasis of the amount of current which has to be supplied to the linearelectric motor for establishing this equilibrium. Moreover, it is alsopossible to actuate the linear electric motor for further deflection ofthe yarn by means of the lever so as to draw back the yarn after aninsertion process or in the middle of a process in the course of whichthe yarn is inserted in a rapier loom.

U.S. Pat. No. 2,202,323 discloses a yarn tensioner which, by means of anapplied weight, deflects the yarn from a straight path more than once.The produced braking effect on the yarn depends exclusively on theweight applied. In the case of a tension drop, e.g. after yarn breakage,the yarn tensioner is, due to a weight applied, displaced to a positionin which an electric contact is actuated and a switch-off signal isproduced.

U.S. Pat. No. 3,633,711 discloses a yarn brake with rerouting anddeceleration of the yarn at several points between brake pads actinglike a pair of tongs, said yarn brake being adapted to be controlled bya cam drive or a magnet.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a loom of the typementioned above with an insertion brake which is universally usable andwhich permits optimization of the insertion processes and a reduction ofthe number of yarn breakages in combination with a high insertion speedand a high insertion frequency.

The objective of the present invention is achieved by means of aprogrammable insertion brake, which can precisely control and reduce theincreased tension within the weft yarn that occurs during the end of theinsertion process of the loom. By moving the insertion brake in theopposite direction, the length of the weft yarn section previouslystored in the insertion brake can be, at least partially, resuppliedduring the tension reduction stage, thereby counteracting the subsequentand undesirable increase in tension and withdrawal of weft yarn. Astepping or d.c. motor displaces the braking element in a manner whichis strictly dependent upon the control program, the weft yarn being atno time capable of automatically effecting a modification or eliminationof the rerouting, unless such modification or elimination is forced uponor offered to the weft yarn by the braking element. In view of the factthat an elastic component is missing, the deceleration of the weft yarnand the reduction of tension within the yarn is carried out exclusivelyby means of the programmed control of the insertion brake, said controlbeing between insertion processes or even during an insertion process. Ahard jolt at the end of the displacement of the insertion brake isavoided, since said insertion brake does not strike a stop means.Instead, it is precisely controlled by means of cams with respect to itsacceleration, deceleration and reversal of its direction of movement.This results in a minimum amount of mechanical wear to the activecomponents. In view of the fact that the control of the insertion brakeis effected electronically, exact reproducible control processes can becarried out in critical phases which last only for a few milliseconds.An adaptation to varying operating conditions of the loom can be carriedout just as an adaptation to the respective yarn quality, or toinsertion speeds which may vary for the same weft yarn. In view of thefact that this structural design guarantees that the insertion brakeworks according to the program in question without any influence on thepart of the weft yarn, a self-learning, adaptive control system can berealized by processing additional information in the control device,which normally includes a microprocessor. This type of control systemcan, to a very large extent, guarantee an optimized insertion processes,i.e. each insertion process is finished with a properly stretched andundamaged weft yarn within the period of time predetermined by the loomand the weft yarn is treated in said insertion process so carefully thatthe number of yarn breakages will be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the subject matter of the invention are explained on thebasis of the drawing, in which

FIG. 1 shows a schematic representation of an air-jet loom with a weftyarn feeder at the end of an insertion process,

FIG. 2 shows a diagram for elucidating the insertion process,

FIG. 3A,3B show two associated fragmentary sections of a firstembodiment of an insertion brake,

FIG. 4A,4B show two associated fragmentary sections of an additionalembodiment of an insertion brake, and

FIG. 5 shows a schematic representation of an additional embodiment ofan insertion brake.

DETAILED DESCRIPTION

A loom W according to FIG. 1 is an air-jet loom 1 provided with a shed 2and a reed 3. Sections of a weft yarn are inserted into the shed 2 inaccordance with the operating cycle of the loom; at least one mainnozzle 5 and, along the shed 2, auxiliary nozzles 4 are provided fortransporting the weft yarn sections; said nozzles being activated anddeactivated in accordance with the operating cycle of the loom. Acutting device 6 is provided downstream of the main nozzle. The weftyarn Y is drawn off a weft yarn feeder 7 which keeps a plurality ofturns at a stand-by position on a storage body 8. The yarn feeder 7 hasprovided therein a stopping device 9 with a stopping element 11 which isretracted for releasing a weft yarn section of exactly measured lengthand which is returned to the stopping position shown when the weft yarnsection has been drawn off. Furthermore, a passage sensor 10 is providednear the stopping device 9, said passage sensor 10 producing a passagesignal whenever the weft yarn passes during the insertion process andtransmitting said passage signal to a control device 12 which controls,among other components, also the stopping device 9. A programming part13 of a control circuit is provided near the control device 12, saidprogramming part 13 serving to control a weft yarn insertion brake 14,which is arranged downstream of the weft yarn feeder 7, during eachinsertion process. The insertion brake 14 is provided with a drivingmotor 15 for movable braking elements 17, which are adapted to bedisplaced relative to stationary rerouting elements 16. A driving motorproven to be particularly useful in practice is an escap stepping motor,type P 430, with a winding in series or a winding in parallel and with atorque of up to 80 Nmm and up to 10,000 steps per second.

In FIG. 1, an insertion process has been finished. The weft yarn Y hasreached the shed end lying opposite the yarn feeder. The insertion brake14 decelerated the weft yarn toward the end of the insertion process.The stopping element 11 is in the stopping position. The next step isthat the inserted weft yarn is cut and beaten up by the reed 3.Subsequently, a new insertion process is initiated by the main nozzle 5and the stopping element 11 is retracted again. The insertion brake 14can be moved to its position of rest where it permits free passage ofthe weft yarn Y.

The diagram of FIG. 2 clearly shows, in the upper part thereof, aninsertion process on the basis of the tension behavior of the weft yarnY. Curve A, which consists of a solid line, represents the tensionbehaviour achieved by use of the controlled insertion brake 14. The partP of the curve consisting of a broken line represents a tension peak ofthe type occurring at the end of the insertion process due to astretching or whipping effect in the weft yarn stopped by the stoppingelement 11. This tension peak is to be reduced because it interfereswith the insertion process and is dangerous to the weft yarn (weft yarnbreakage). The tension drop a at the beginning of the curve A representsthe start of movement of the weft yarn at the beginning of the insertionprocess as soon as the stopping element 11 has released the weft yarn.Following this, the weft yarn is accelerated until it has reached itsinsertion speed, the tension behaviour being comparatively constant inthis area. Towards the end of the insertion process, viz. a certainperiod of time prior to the expected occurrence of the tension peak P atthe moment tP, the insertion brake 14 is moved to its braking positionso that the weft yarn will be deflected and rerouted and decelerated bymeans of friction. This will cause a first increase in tension b and asecond increase in tension C which is approximately time-coincident withthe tension peak P. Subsequently, the tension decreases before a small,significant tension drop d represents the cutting of the weft yarn andbefore an increase in tension e finally represents the beating up by thereed. The time required for an insertion process is shown on thehorizontal axis, whereas the vertical axis indicates, in the upwarddirection, the tension in the weft yarn.

The passage signals No. 1-7 of the passage sensor 10, which occur by wayof example during an insertion process, can be seen on the lowerhorizontal time axis in FIG. 2. Without any braking, the tension peak Pwould occur during each insertion process in a fixed temporalrelationship with a passage signal, e.g. passage signal No. 7. Thecontrol of the insertion brake 14 is therefore related to the passagesignals so as to permit the insertion brake to be moved in the oppositedirection by means of the control device 12 in due time. Curve Brepresents the movement of the insertion brake 14 for a predeterminedperiod of time and with a positive magnitude of a deflection stroke e.g.an angular stroke of 30°. The front part of curve B, which consists of abroken line, clearly shows the response time R of the insertion brake14. In order to achieve a movement of the insertion brake 14 over thearea represented by the solid-line curve B, the brake has to beactivated at the moment ta after the passage signal No. 4. The curve,which consists of a dot-dash line and which is superimposed on thesolid-line curve B, shows clearly that also the control of the insertionbrake 14 can be varied, e.g. in a steplike manner, for achieving firstan abrupt and intensive deceleration with strong rerouting anddeflection of the weft yarn and for reducing afterwards the reroutingand the deflection to a certain extent, along with releasing the weftyarn stored in the insertion brake 14 so as to counteract an undesiredincrease in the tension of the weft yarn, so as to have the weft yarn inthe shed in a stretched condition, the stretching being effected by thethen additionally activated last auxiliary nozzles 4. When the passagesignal 4 has occurred, the control device 12 will wait for the moment taprior to activating the insertion brake 14.

Curve C, which consists of a solid line, represents e.g. a movement ofthe insertion brake 14 beyond the position of rest into the otherdirection, e.g. for activating (as will be explained later on) athreading nozzle for automatic threading of a weft yarn or a nozzle ofthe insertion brake.

The insertion brake 14 according to FIG. 3A and 3B comprises a basicbody 18 at which a stationary rerouting point 19 is defined by aneyelet. Two spaced stationary rerouting elements in the form of pins, 20and 21, are secured to the basic body 18 on one side of the path of theweft yarn through the insertion brake 14. Furthermore, a carrier 25 fortwo movable braking elements 26 and 27 is adapted to be rotated on thebasic body about a vertical adjustment shaft 22. The carrier 25 isconstructed as an inelastic lever, and it is connected to a drivingmotor 24 via an inelastic connection shaft 23, thereby assuring aslack-free coupling between the drive motor and brake element. Thedriving motor 24 is arranged below the basic body 18, and driving motor24 is a fast-response stepping motor or d.c. motor; it will be expedientto provide said stepping motor or d.c. motor with a resolver fordetermining the rotary or angular movement of the motor shaft.

As soon as the driving motor 24 is moved from its position of rest, asshown in FIG. 3A, in a counterclockwise direction through the controldevice 12 within the framework of the program for controlling theinsertion brake 14, the braking elements 27 and 26 will pass between thestationary rerouting elements 19, 20 and 21 and move across the yarnpath. The weft yarn will be rerouted and deflected as well asdecelerated. At the same time, a yarn section whose length depends onthe geometry of the individual elements and the stroke of the drivingmotor 24 will be stored in the insertion brake 14. As soon as thebraking process has been finished, the driving motor 24 will again bemoved in the opposite direction, either with a predetermined stroke orfully up to its position of rest. In addition, a clockwise controlmovement of the driving motor 24 in FIG. 3A, in accordance with curve Cin FIG. 2, is also possible for displacing the movable braking elements26, 27 even farther than the position of rest and for initiating adifferent function.

In the case of the embodiment of the insertion brake 14 according toFIG. 4A and 4B, a total number of six rerouting points for the weft yarnis provided. In this embodiment, expediency is maximized when an overallrerouting angle of up to 700° is achieved. The two stationary reroutingelements 19 and 19', which are defined by eyelets, are provided on thebasic body 18 in the weft yarn path. Two inner stationary reroutingpoints 20 and 21 are formed at a tube 28 held coaxially with the weftyarn path by means of a component 38 of the basic body. The movablebraking elements 26 and 27 are attached to their lever-like carrier 25and adapted to be rotated together therewith about the centraladjustment shaft 22. FIG. 4A represents the position of rest and, withthe aid of the drive means 24 and via the connection shaft 23, thecarrier 25 is adapted to be moved from said position of rest in acounterclockwise direction for deflecting and decelerating the weftyarn. In the course of this process, the two movable braking elements26, 27 move across the weft yarn path from opposite sides between theinner stationary rerouting elements 20 and 21 and the outer stationaryrerouting elements 19 and 19', respectively.

The part of the basic body 18 where the feed yarn is supplied isprovided with a threading nozzle 29 comprising a funnel-shaped inlet 30for the weft yarn and a nozzle means 31, where compressed air comingfrom a pressure source 34 can be guided through the insertion brake andthe tube 28. The threading nozzle 29 is used for automatically threadingthe weft yarn after yarn breakage or for the initial threadingoperation. The threading nozzle 29 is connected via a line 32 to anon-off valve 33, which is adapted to be switched between a passageposition and a blocking position by means of a switching magnet 35 andwhich interconnects the pressure source 34 and the threading nozzle 29in said passage position. The magnet 35 is connected to a switch 37 viaa line 36, said switch 37 being arranged in the area of movement of e.g.the carrier 25 on the insertion brake 14 or in the vicinity thereof. Ifthe carrier 25 is displaced clockwise to a certain extent from itsposition of rest (in accordance with curve C of FIG. 2), the switch 37will be closed and the on-off valve 33 will be switched to its passageposition. This switching process can be initiated in accordance with theprogram in question via the control device as soon as said controldevice has supplied thereto e.g. an error message or a yarn breakagemessage. The tube 28 supports correct flow guidance during the weft yarnthreading process. The on-off valve 33 may also be actuated directly bythe carrier 25. If it is constructed as a control valve, the flowthrough the nozzle 29 can be modulated continuously or in steps by meansof the driving motor 24. The tube 28 can be constructed as a secondarystationary main nozzle used for threading and/or for purposefully movingthe weft yarn and can be actuated by controlling the driving motor 24 inan adequate manner.

In the case of the embodiment according to FIG. 5, the movable brakingelements 26, 27 of the insertion brake 14 are adapted to be movedlinearly between the stationary rerouting elements 19, 20, 21 forrerouting the weft yarn Y and for deflecting and decelerating it. Thebraking elements 26, 27 are located on the carrier 25, which, via aslide member 39, is controlled by the driving motor 24' constructed as alinear motor. It will be expedient when the driving motor 24' is astepping motor or a d.c. motor.

By means of the electronically, cam-controlled insertion brake describedabove, along with its adaptive control system, the following advantagesand important functions are obtained:

An overall low tension is maintained within the weft yarn, from which aconsiderable reduction in the number of thread breakages or of otherinsertion faults results.

In view of the fact that, due to the cam control, the weft yarn is lessabruptly stopped than in previous systems, and in view of the fact thatthe weft yarn no longer retracts either, the function of the auxiliarynozzles arranged in the shed can be throttled towards the end of theinsertion process, resulting in a lower nozzle pressure combined with alower consumption of air for cases of filament or broad-width fabriclooms.

Due to the fact that the weft yarn is quickly stabilized at the end ofthe insertion process, it is possible to adjust, after the insertionprocess, shorter periods of time which will elapse until the shedchanges. This will result in a longer period of time which is actuallyavailable for transporting the weft yarn. This is achieved without anyincrease in pressure in the main nozzle, which frequently leads toadditional malfunctions.

The insertion brake is, at least, self-compensating, since the use oflower weft yarn speeds and lower tensions has the effect that thefrictional force effective during the braking operation is reduced aswell.

For the purpose of rapid stabilization of the weft yarn and the end ofthe insertion process, it is, due to the individual and fast-respondingcontrollability of the insertion brake, possible to move the free weftyarn end to a comparatively advanced position and to draw it thenslightly back or to release, after a minor delay, at least part of theweft yarn length stored in the brake.

Furthermore, the insertion brake can be used for repositioning the wholeweft yarn length at the end of the insertion process and before the reedbeats up, e.g. with respect to an improvement of the means processingthe boundary edge of the fabric.

If several weft yarns are processed alternately, the free end of a weftyarn in a stand-by position can be drawn back in the channel so that onefluttering weft yarn end will not interfere with the other weft yarn.This drawing back by means of the controlled insertion brake, or ato-and-fro movement of the weft yarn end in the main nozzle, willdistribute the mechanical influence (fibre dissolution) in the case ofweft yarn which is not inserted for a prolonged period of time, saidmechanical influence being thus reduced to a negligible extent.

Furthermore, by means of a program-dependent displacement of theinsertion brake at the beginning of the insertion process, a weft yarnlength is released which has been stored previously, i.e. after the endof the preceding insertion process, so that the weft yarn end, supportedby the main nozzle or the auxiliary nozzle, will already start itsmovement before the stopping element in the weft yarn feeder releasesthe weft yarn. This permits a reduction of the peak velocity of the weftyarn during the insertion process without exceeding the necessaryinsertion period.

By resupplying the stored weft yarn length in a very rapidly controlledmanner after the end of the insertion process and during the beating upof the reed and the cutting operation, respectively, the tensionvariations resulting from these operations are reduced. For thispurpose, the control circuit may have provided therein a special logicaldriver circuit.

The braking operation is carried out with a complex stroke/time programso that an adaptive control of the weft yarn speed can be achieved. Itis, in this connection, possible to control not only a correct maximumstroke of the insertion brake, but to follow a specific position/timediagram for the insertion brake movement in the course of which theinsertion brake carries out a plurality of functions at the weft yarn.Since similar type yarn, under unchanged insertion conditions, will movefaster towards the end of a supply coil than it did when the supply coilwas still full, a weak deflection effected by the insertion brake canthrottle the weft yarn speed to the desired value when this part of theyarn is being processed. The insertion brake is, so to speak, aninsertion brake that realizes a plurality of braking steps.

A particularly effective reduction of the tension peak at the end of theinsertion process is achieved when, in the maximum deflection conditionand, consequently, in a condition in which the maximum braking effect isproduced, the insertion brake releases the stored yarn length veryrapidly, at a speed of up to 20 m/sec, before the weft yarn develops itstendency to spring back. This necessitates the rapid reversal of thedirection of movement and the positive connection in the insertion brakeas well as a driver logic section in the control program.

In summary, it is seen that an insertion brake with a multi-functionalrange of use is created by positively connecting a precise andcontrollable driving motor with the necessary braking elements. Then byincluding an intelligent and flexible control device, the subsequentlyformed insertion brake fulfills its main task of damping or suppressingthe whipping effect within the weft yarn, along with optimizing theinsertion process of the loom.

We claim:
 1. A loom provided with an insertion brake for controlling themovement of weft yarn being processed within said loom, comprising:atleast one braking element movably arranged within said insertion brakeso as to be displaced across a path of said weft yarn, said brakingelement moving from a position of rest on one side of said weft yarn toat least one braking position for deflecting and rerouting said weftyarn at rerouting elements arranged in a stationary manner on anotherside of said weft yarn; an electric driving motor connected to saidbraking element by means of a positive connection which is inelastic inall directions of movement, said driving motor adapted to be actuatedduring each insertion process of said loom and capable of being operatedin each direction of movement, a stroke of said driving motor beingadjustable in each set position of said braking element during saidinsertion process of said weft yarn; and a programmable control devicefor controlling the timing, stroke and direction of movement of saiddriving motor, the control device having a programming capable of beingmodified at least at a time between a first and subsequent insertionprocess of said loom; wherein a force exerted by said driving motor andacting upon said braking element is greater than a possible maximumreaction force of said deflected weft yarn.
 2. A loom according to claim1, wherein said electric driving motor is one of a fast-responsestepping motor and a d.c. motor.
 3. A loom according to claim 1, furthercomprising at least one controllable nozzle located on a yarn-feedingside of said loom and associated with said insertion brake, wherein saidnozzle can be activated by said control device and can be modulated in acontrolled manner so as to obtain a desired blowing effect.
 4. A loomaccording to claim 1, wherein said programmable control device furtherincludes a driver logic section which allows for a controlled, rapidrelease of a length of said weft yarn stored in said insertion brake. 5.A loom according to claim 1, wherein said programmable control devicefurther includes program routines for storing a length of weft yarnafter an end of said insertion process, and for releasing said storedweft yarn length for an initial acceleration of a leading end of saidweft yarn.
 6. An insertion brake for a loom, comprising:at least onebraking element movably arranged within said insertion brake so as to bedisplaced across a path of a weft yarn, said braking element moving froma position of rest on one side of said weft yarn to at least one brakingposition for deflecting and rerouting said weft yarn at reroutingelements arranged in a stationary manner on another side of said weftyarn; an electric driving motor connected to said braking element bymeans of a positive connection which is inelastic in all directions ofmovement, said driving motor being one of a fast-response stepping motorand a d.c. motor and adapted to be actuated during each insertionprocess of said loom and capable of being operated in each direction ofmovement, a stroke of said driving motor being adjustable in each setposition of said braking element during said insertion process of saidweft yarn; and a programmable control circuit which can be containedwithin a control device of said loom, said control circuit controllingthe timing, stroke and direction of movement of said driving motor, thecontrol circuit having a programming capable of being modified at leastat a time between a first and subsequent insertion process of said loom;wherein a force exerted by said driving motor and acting upon saidbraking element is greater than a possible maximum reaction force ofsaid deflected weft yarn.
 7. An insertion brake according to claim 6,wherein said insertion brake is constructed as a deflection brake, andfurther comprises a plurality of stationary rerouting elements and aplurality of braking elements which can be moved so as to pass betweensaid stationary rerouting elements, wherein said braking elements areattached to a carrier, and said carrier is attached to said drivingmotor by means of the positive connection.
 8. An insertion brakeaccording to claim 7, wherein said carrier is rotated about anadjustment shaft, and that said adjustment shaft is defined by aconnection shaft extending between said driving motor and said carrier.9. An insertion brake according to claim 8, wherein said connectionshaft is rotatably supported in said driving motor.
 10. An insertionbrake according to claim 7, wherein said deflection brake is providedwith at least two stationary rerouting elements and with at least twomovable braking elements.
 11. An insertion brake according to claim 7,wherein said carrier is adapted to be displaced linearly in a directiontransversely to a weft yarn direction, and the positive connection isestablished between said carrier and said driving motor.
 12. Aninsertion brake according to claim 7, wherein a resolver is incorporatedinto said control circuit for detecting angular movements of a motorshaft of said driving motor.
 13. An insertion brake according to claim7, wherein said deflection brake is provided with two outer and twoinner stationary rerouting elements and with two braking elementsadapted to be moved between said outer and said inner reroutingelements, respectively, and that said two braking elements are arrangedclose to the ends of said carrier, which is centrally rotated about saidadjustment shaft, said braking elements being arranged substantially atidentical distances from said adjustment shaft.
 14. An insertion brakeaccording to claim 7, wherein said insertion brake, when occupying itsbraking position, has an overall weft yarn rerouting angle of up to700°.
 15. An insertion brake according to claim 13, wherein said twoinner stationary rerouting elements are arranged in a tube which iscoaxial with said weft yarn path and which forms an air guide passagethrough which said weft yarn may be reliably threaded.
 16. An insertionbrake according to claim 15, wherein said tube is constructed as athreading nozzle for controlled threading and acceleration of said weftyarn before said insertion process starts.
 17. An insertion brakeaccording to claim 15, wherein a rate of flow through said threadingnozzle can be varied during said insertion process, by means of saiddriving motor of said insertion brake.
 18. An insertion brake accordingto claim 6, wherein an on-off switch for activating a threading nozzledirected towards a path of said weft yarn between said braking andrerouting elements is provided adjacent said insertion brake, saidon-off switch being actuated by said driving motor.
 19. An insertionbrake according to claim 18, wherein said braking element and drivingmotor, when controlled such that they move from said position of rest ina direction of movement opposite to a direction of said brakingpositions, are respectively moved to at least one threading position,and that said on-off switch for said threading nozzle is in alignmentwith a threading position of said braking element and driving motor,respectively, for the purpose of actuation.
 20. An insertion brakeaccording to claim 19, wherein a rate of flow through one of saidthreading nozzle and a secondary main nozzle can be modulatedcontinuously or in steps by means of said driving motor.